Perhaps the United States needs to take a step back and look at there problems. More guns is not a solution it is a very brittle band aid at best. The US needs to figure out what the problems are and put aside party politics and solve it. If you can spend over half a trillion on the US Military I think you can spend a few billion on taking a look at this issue and then put some serious thought and effort into solving it.
You can't sue the government for making a law that would suddenly make it illegal for you to own your guns. You could easily come back from a tour of duty with a mild case of PTSD. If you went to see a therapist you could be deemed mentally ill and unfit to own your firearms. There would be nothing you could do about it. New York's new idiotic gun laws didn't exempt police officers from having a gun in their homes and now, technically, they are breaking the law.
I know very well what the problem is, without spending a few billion dollars. Criminals commit crimes with illegal guns and get a slap on the wrist. They spend little to no time in jail and continue to commit crimes while they are on probation or out on bail awaiting trial. There is virtually no deterrent for them.